A disgruntled security guard was behind a deadly shooting at a northwest Harris County meat market Saturday, authorities said.

Harris County Sheriff's Office deputies told us the gunman -- 56-year-old Gregory Griffin -- lost his job as a security guard for the business, and he took out his anger on his replacement.

Just two candles mark the spot where Jose Argueta took his last breath Saturday outside La Veracruzana, a meat market and taqueria in the 1200 block of West Road at Veterans Memorial.

"I just hate that it happened like this," customer Sharon Buchanan said.

Investigators spent much of the afternoon and evening talking to Griffin, who they tell us used to be a security guard with Texas Pioneer Control Officers. They said he was fired about three weeks ago but kept coming back to La Veracruzana to work.

According to detectives, things came to a head around 2pm Saturday when his replacement, Argueta, confronted him.

"One of the business owners told him that he wasn't to be working here, that he no longer worked for the security company," HCSO Sgt. Robert Spurgeon said. "The security guard confirmed everything. The new security guard who was replacing him said he had been terminated at which time he pulled his weapon and shot the security guard that was replacing him."

Argueta, 38, died at the scene. Both men were wearing their security guard uniforms.

Buchanan said she knows both men. She said Griffin had confided in her recently. What he told her upon learning his job was in jeopardy is weighing heavily upon her now.

"[He said,] 'I don't know why they treat me like that. I'm not fixing to leave my job,'" Buchanan said. "He say he was going to stay there and he was going to work."

No one at the store was willing to comment about the incident. Texas Pioneer Control, the company which employed the two guards, did not return our calls.

Griffin was arrested at the scene and charged with murder.

Please stay with Eyewitness News and abc13.com for updates as we continue following this story.